2, 3, 6-tris-aziridino-1, 4 benzoquinone



United States Patent ()fiiice 2,3,6-TRIS -AZlRIDINO-L4 BENZOQUINONEWalter Gauss,.Leverkusen-Bayerwerk, Leverkusen, and

Gerhard. Domagk', Wuppertal 'Elberfeld, Germany assiguors to. S'chenley.Industries, Inc.,. a corporation. off Delaware No Drawing. Filed Mar;11; 19.58,;Ser. No.720,s4a Claims priority, application GrmanyMar;14,1951

1 Glaim'; or. 260-239)- This invention relates generally tocertai'rrnovel organic chemical compounds useful in chemotherapy, together withprocess for producing the same, and morev particularly is concerned withcertainnovel aziridinoquinones and aziridi'nohyd'roquinones that areuseful in treatment of amebiasi's, i'ncludingamebic colitis, amebichepatitis, amebic abscesses, and 'amebic dysentery, produced by theparasitic microorganism, Entamoeba histolytica.

It is well known that human-diseaseconditions, produced by theparasitic. microorganism Entamoeba. histolyticapresent aseverepublichealth problem, especially in tropical countries and in.localities where propersanitary precautions are not. observed.Heretofore, acute cases. have been treated, with emetine hydrochloridead: ministered subcutaneously, but this. drug hastbe. disadvan- :tagethat. while it. is. active, against the tropliozoites, it is inactiveagainst. the amebic. cysts, hence it is. notv useful to eliminatechronicamebiasi's, or carriers. AJfurther' disadvantage. of. this drug. is itshigh toxicitywhich. can result in fatal effects if. the administration.accidentally is intravenous instead of. merely subcutaneous.

Another compound that has been used in treating amebiasis is.5,7.-diiodo -S-hydroxyquinoline but this. compound like emetine, has thedisadvantage of not being effective against the amebic cysts, inthiscase due. to excessively rapidabsorption of the drug before itcan becarried tothe lumen of the bowel. It follows therefore that these drugswhich are commonly regarded as the best chemotherapeutic agentscurrently available for molecular substituents in the 2 and 6positions-, with possible further substitution: of. a third. aziridino,group in the 3 position. Solutions of these compounds. show highactivity against Entamoebw histolytica in dilutions of 1210Specifically, the novel compounds of this invention are substanceschosen from the group consisting of 2,6-bisaziridino 1,4benzohydroquinone, 2,6-bis-aziridino-l,4- benzoquinone and2,3,6-tris-aziridino-1,4-benzoquinone. It is known thatpara-benzoquinones having in the ortho position at least one loweralkoxy group of a type exchangeable with an amine group to produce anamino substituent group are capable of reacting with aziridine andsubstituted aziridines to produce ortho-azin'dinopara-benzoquinones. Itis also known that this reaction takes place with2,5-bis-alkoxy-l,4-benzoquinones to produce corresponding2,5-bis-aziridino compounds. Heretofore, however, no 2,6bis-aziridino-1,4-benzoquinone' or 2,6biseazirdino-l,4-benzohydroquiuone have beenv prepared because. theorienting effect has been regarded as being such that compounds. of thismolecular configuration would not be produced.

In accordance with certain of. the process aspects of the presentinvention, a novel method is provided for making derivatives ofl'A-benzohydtoquinone and 1,4- b'enzoqui'none bearing aziridino groupsas substituents in the 2 and 6 positions. The process involves controlof the reaction environment in terms of use of a diluent,

a substantial excess ofioneof the reactants, prolonged reaction at. roomtemperatures and. reaction under anaerobic conditions. In this process,using 1,4-benzoquinones having in each of the 2 and 6. positions a loweralkoxy substituent, the reaction products obtained are mixtures of2,6-bis+aziridino-benzohydro'quinone and2,3,6-tris-aziridino-benzoquinone. The reaction products maybe separatedfrom each other and the reaction mixture in conventional manner. bymethods based upon use of preferential:solvents..

Among the 2,6-dialkoxy 1,4-benzoquinones that may be; used as.startingrmaterials in practice of'the Process according to thisinvention-may be mentioned" compounds in WhiCh' the al-koxy group isthat derived from a lower alkanol; e.g., oneahaving at mostv 4 carbonatoms in the chain: Of the compounds of this group, 2,6-dimethoxy- 1L4-benzo'quinone: is: chiefly preferred. a

i It; is: preferred to perform-.theprocess according to this inventionby, mixing the reactants, the- 2,6-bis-alkoxy- 1,4-benzoqui'none-and:aziridine, inan inert liquid diluent, suchras a-lower alkanolI-having atmost 4 carbonatoms in its: chain, and under anaerobic conditions,permitting the reactants to enter: into: reaction at a controlledtemperature of at most room temperature (about 20" C.) or, preferably,ata lower temperature, for instance, 0 C. or thereabouts. Initially thebenzoquinone reactant remains undissolvediin the reaction mixture but.as, it enters into reactiont aziridine it. passes into solution,simultaneously producing-both a colorless and a colored reaction productwhich is precipitated from the reaction mixture. It is, evident that.the reaction products: dilfer fromthe undissolved reactant from the.fact that they are of different. colors, i-.e., using2,6-dimethoxy-1,4-benzoquinone, which is a yellow substance, asa-reactant with aziridine, a colored suspension is produced withprecipitated colorless and purple reaction products which are. separatedfrom. the. mixture by filtration immediately after the last portion:ofthe yellow starting material passes into reaction 'T'heseparatedreaction products are separated from each other by use of preferential.solvents, for example, the purple precipitate can'be leached from themixture of, solids by use of cold acetone, benzene or chloroform andrecovered from the leaching: solution: by solvent evaporation. It may:be purified by recrystallization from acetone or ethyl acetate. and isfound to be: 2,'3.,6-tris .aziridino-L4-benzoquinone having; anempirical -formula C H N O and melting at 162.5 to 163.0 Theprecipitated colorless reaction product which, surprisingly, is2,6-bis-aziridino-1,4-benzohydroquinone, may

be purified by recrystallization from dioxane or other 2,976,279]Patented Mar. 21,, 1961- This oxidation reaction preferably is carriedout in a solvent reaction medium which may be an aqueous, or ganic, oraqueous-organic medium. A suitable oxidizing agent for this purpose ispara-benzoquinone. The reaction product, 2,6-aziridino-1,4-benzoquinonevis obtained (after recrystallization) as an orange-colored crystallineproduct melting at 166-167 C. with decomposition. It may bedilferentiated readily from the known 2,5-bis-aziridino-1,4-benzoquinoneand also from the 4,5-bis-aziridino-1.,2-benzoquinone described in,Beriche 89, 2768-73 (1956).

Each of the three reaction products above mentioned is active againstthe parasitic microorganism Entamoeba histolytica.

To facilitate a fuller and more complete understanding of the subjectmatter of this invention, tw'o specific examples herewith follow but itis clearly to be understood that these examples are provided by way ofillustration merely and are not to beconstrued as imposing limitationsupon the scope of the invention defined in the subjoined claim.

Example 1 Under anaerobic conditions including an atmosphere ofnitrogen, 104 cubic centimeters (2.0 moles) of aziridine is added as asingle portion with stirring to a suspension of 33.6 grams (0.2 mole) of2,6-dimethoxy- 1,4-benzoquinone in 500 cubic centimeters of absolutemethanol at "a temperature of to C. After'the addition has beencompleted the external cooling of the reaction vessel is replaced by aroom temperature water bath and the mixture is stirred at roomtemperature for 45 hours while a slow stream of nitrogen is passedtherethrough to preserve the anaerobic reaction conditions. It is foundthat the yellow starting material, during this period, completelydisappears into solution and that a violet or purple substance togetherwith a colorless substance are formed as precipitated reaction products.This mixture of precipitated products is removed by filtration at C. andthe residue is washed with a small quantity of cooled methanol. Then themixture is dried in a vacuum desiccator yielding about 30.4 grams ofmixed product. The mixed product is The benzene extract of the coloredreaction product is evaporated to dryness under vacuum, yielding aresidue melting at 161-162 C. which is recrystallized from 200 cubiccentimeters of ethyl acetate, filtered under suction at 20 C., washedwith cold methanol and thus yields about 11.5 grams of a pure,purple-colored crystalline product melting at 162.5-163 C. This productis 2,3,5-tris-aziridino-1,4-benzoquinone, having an empirical formula CH N O, and a molecular weight of 231.25. Analysis of this product afterdrying under high vacuum for 2 hours at C. revealed the following data:

Calculated: (3,6232; H, 5.67; N, 18.17; 0, 13.84. Found: C. 62.27,62.51; H, 5.77, 5.76;. N, 18.06, 18.14; 0, 14.13.

This substance is active against the microorganism Entamaeba histolyticain dilution of 1:10 and is active even in a dilution of 1:10

If the foregoing operations are performed under aerobic conditions i.e.,in an atmosphere of oxygen, the yield of2.,6-bis-aziridino-hydroquinoneis reduced to 0.36 gram and the remainderof the mixture consists of products that fail to crystallize but insteadquickly turn to an insoluble resin.

Example 2 under suction-andthe residue is washed with a mixtureextracted with benzene whereby the violet or purple colored componentpasses into solution and the substantially colorless product remains ina yield'of about 16.0 grams. The colorless product so obtained meltswith decomposition at about 221222 C. with melting starting at about 200C. It can be purified by recrystallization from a large column ofdioxane yielding snow-white crystals that decompose when heated at 222-224 C. while starting to melt at 220 C.

Analysis of a sample of this material after drying under high vacuumestablishes that the substance is 2,770,617 Marxer Nov. 13, 19562,6-bis-aziridino-1,4benzohydroquinone having the empirical formula C HN O and a molecular weight of 192.21. Analysis revealed the followingdata:

Calculated: C, 62.48; H, 6.29; N, 14.58. Found: C, 62.13, 62.31; -H,5.98, 6.22; N, 14.70, 14.65.

This substance is active against Entamoeba histolytica in a dilution of1:10 and even in dilutions as great as 1:10 'it retains activity againstthis parasitical microorganism.

- of equal parts methanol and water at a temperature of '20 C. Theresidue is recrystallized from methanol, yielding red crystallineneedles that melt with decomposition at 166-167 C. and which areidentifiable as 2,6-bis aziridino-1,4-benzoquinone having an empiricalformula cloHloNgog and a molecular weight of 190.20. After drying,- theproduct upon analysis yields the following data:

Calculated: C, 63.15, H, 5.30; N, 14.73. C, 62.96, 63.11; H, 5.29, 5.34;N, 15.15, 15.06;

This substance is active against the microorganism Entamoeba histolyticain dilution of 1:10 and remains active even when diluted to 1:10

Having thus described the subject matter of this in- Found verition,what it is desired to secure by Letters Patent of the United States is:

. A's'a new composition of matter, 2,3,6-trisaziridino- References Citedin the file of this patent UNITED STATES PATENTS OTHER REFERENCESAngewandte Chemie, vol. 67, p. 227

